To obtain impressions of teeth in order to produce a denture, use is made of impression compounds which harden from a pasty state. In order to hold the impression compound in the area of the teeth from which the impression is being taken, impression trays are used. These consist of a base and of at least two side walls which together enclose the impression area into which the impression compound is introduced so as to be brought, held by the tray, to the impression site. The walls, one of which comes to lie on the lingual/palatal aspect and the other on the buccal aspect of the teeth from which the impression is to be taken, are intended to ensure that the compound cannot flow out but is instead held at the sides of the teeth from which the impression is to be taken. It is known (DE-A-196 08 546) to provide, in the tray, a delivery tube for the compound, which delivery tube is provided with a row of outlet openings distributed along the length of the tray.
As a result of the closing of the dentition during impression-taking, the teeth from which the impression is to be taken force themselves into the impression compound. This is not successfully accomplished if the patient bites on one of the two walls and, accordingly, the teeth from which the impression is to be taken do not penetrate into the space between the walls. This risk arises in known impression trays which are made of a rigid material such as metal or plastic. If, according to a known proposal (DE-C-31 04 721), the compound is enclosed entirely within a flexible tube, the tube material located between the compound and the teeth forms an obstacle to a clean impression. Furthermore, the unpublished prior art includes the proposal that fixed walls be avoided by means of the walls being formed by inflatable tube elements.
Compressed air, water or else impression compound can be used to fill the tube elements. However, it has been found that, on account of the lack of shape stability of such impression trays, the impression compound is not securely held and, for example, flows out over the walls. The impression material does not then attain the desired height, and the impression-taking is not completely successful.